Non-stick ceramic coating composition and process

Abstract

A series of new non-stick ceramic coating materials prepared from organic-inorganic hybrid materials, including silica sol, MTMS, FAS and PDMS (Polydimethylsiloxane) using the sol-gel process. The hybrid materials have good mechanical properties and are fashioned into a main ceramic network and good non-stick properties from organic non-stick compounds. The non-stick ceramic coating consists of two layers applied to cookware and for other applications.

1. A non-stick coating composition comprising;
 a colored base layer for bonding to a substrate and a transparent top layer superimposed on and bonded to the base layer; 
 the base layer composed of 70 to 85% by weight of a first matrix comprising the condensation reaction product of a silica sol and methyltrihydroxysilane and from 15 to 30% by wt of a colorant, with about 5 to about 20% by wt of the first matrix being substituted by hydroxy-terminated polydimethylsiloxane having a molecular weight of from about 400 to 6000; said base layer having a distinct lower portion composed principally of the first matrix and colorant, and a distinct upper portion composed principally of said hydroxy-terminated polydimethylsiloxane and said first matrix and colorant, and 
 the top layer composed of a second matrix comprising the condensation reaction product of a silica sol and methyltrihydroxysilane with from about 5 to about 20% by wt of the second matrix being substituted by hydroxy-terminated polydimethylsiloxane having a molecular weight of from about 400 to 6000, and with from about 0.3 to about 12% by wt of the second matrix being substituted by fluoroalkoxysilane. 
 
     
     
       2. A non-stick coating composition according to  claim 1  wherein the fluoroalkoxysilane is present less than about 2 wt % of the second matrix. 
     
     
       3. A non-stick coating composition according to  claim 1  wherein the matrices are comprised of from 30 wt % to about 70 wt % of silica sol, and 2 wt % to 40 wt % of methyltrihydroxysilane. 
     
     
       4. A non-stick coating composition according to  claim 1  wherein a catalyst is present in an amount up to about 2 wt % of the matrices. 
     
     
       5. The non-stick coating composition of  claim 1  wherein from about 5 to 50% epoxy silane is substituted for the first matrix present in the base layer.